Judges at the International Criminal Court on Tuesday issued an arrest warrant for a close ally of renegade Libyan general Khalifa Haftar, over alleged involvement in the execution of dozens of prisoners, many of which were filmed.

Prosecutors at the world's permanent war crimes court are seeking Mahmoud al-Warfalli, dubbed Haftar's "executioner in chief" to face charges of murder while fighting for Haftar's so-called Libyan National Army (LNA).

According to the ICC, Warfalli "is alleged to have directly committed and to have ordered the commission of murder as a war crime" during seven incidents involving 33 people in June and July 2017 in and near Benghazi.

He appears in one video in which 20 people are apparently killed. Graphic footage follows:

The LNA, which controls the eastern part of Libya, has been pushing to expand its presence in the central and southern part of the country where it has been vying for control with forces linked to the UN-backed government in Tripoli and other groups.

The UN called for the LNA to suspend Warfalli after a video in March allegedly showed Warfalli shooting dead three men who were kneeling and facing a wall with their hands tied behind their backs.

The LNA said it would investigate any potential war crimes but has not released any details of such a probe.

In June, two further videos appeared to show summary executions carried out by LNA fighters on his orders.

The ICC has jurisdiction over war crimes in Libya after a referral by the United Nations Security Council in 2011 and has been investigating alleged atrocities there.